Portal Space Systems, founded in 2021 and based in Seattle, is a space startup focused on revolutionizing in-space maneuverability. They are developing the Supernova satellite bus, a payload-agnostic platform powered by a novel solar-thermal propulsion system designed for rapid orbital transfers. With funding from the Department of Defense and Space Force, Portal aims to provide tactical responsiveness and dynamic space operations capabilities. Their primary customer is the U.S. government, specifically the Space Force. Key words: satellite bus, solar-thermal propulsion, in-space mobility, space tug, maneuverability.
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Portal Space Systems is a Bothell-based venture developing highly maneuverable spacecraft for inspecting, servicing, or deorbiting satellites.
Portal Space Systems is a Bothell, Washington-based spacecraft manufacturer founded in 2021 by Jeff Thornburg.
Portal Space Systems’ solar thermal propulsion technology had been validated in NASA and Air Force Research Laboratory programs before commercialization.
Portal Space Systems closed a $50 million Series A in April 2026 at a $250 million valuation.
In September 2025, Portal Space Systems became the first commercial company to successfully test an STP system at operational temperatures inside a vacuum chamber.
The Portal Space Systems Series A was led by Geodesic Capital and Mach33.
Booz Allen Ventures, ARK Invest, AlleyCorp, and FUSE participated in Portal Space Systems’ Series A.
Portal Space Systems plans to scale from 40 employees to 100 employees by year-end 2026.
Portal Space Systems’ Supernova spacecraft is designed to deliver up to 6 km/s of delta-v across orbital regimes from low Earth orbit to cislunar space.
Portal Space Systems’ propulsion system concentrates sunlight directly to heat ammonia-based propellant.
Portal Space Systems has a CEO-stated goal of producing four spacecraft per month by the end of 2027.
Portal Space Systems’ 3D-printed heat exchanger thruster is designated Flare.
Portal Space Systems follows a $17.5 million seed round that was announced in 2025.
Portal Space Systems was founded by former SpaceX engineer Jeff Thornburg.
Portal Space Systems is developing the Supernova vehicle, a solar-thermal propulsion system designed to reduce orbital transfer time.
Portal Space Systems has received private funding and funding from the U.S. Space Force for applications in orbital surveillance and defense against hypersonic threats.
Portal Space Systems raised a $50 million Series A at a $250 million valuation for high-power solar-thermal propulsion.
Portal Space Systems previously raised a 17.5 million dollar seed round in 2025.
Geodesic Capital and Mach33 led Portal Space Systems' Series A financing, with participation from Booz Allen Ventures, ARK Invest, AlleyCorp, and FUSE.
Portal Space Systems closed a 50-million-dollar Series A round.